1. Field of the Invention
The present invention relates generally to enclosures for receiving and storing digitally coded discs and, more particularly, to an improved disc retaining means for holding such discs within such enclosures.
2. Description of the Prior Art
Various types of planar discs are in use at the present time to record and store information which is to be retrieved by various means, such as by optical or magnetic means. Typical of such discs are compact discs (CDs) in which information is digitally recorded by use of a laser beam and then read optically by a laser beam. Such discs are used to record audio information, such as musical renditions, video information such as visual images and digital information for use as read only and other memories for use in various applications, such as computer applications. In most instances, at the present time, such discs are sold with information already recorded thereon. In other applications, such discs are sold in blank form and are used by the customer to record information thereon. In the latter case, for example, optical discs are sold for use as computer storage media and are used in hard disc storage systems. In either case, optical imperfections in or on the surfaces of such discs interfere with both the recording and retrieval of information stored on the discs. Care must, therefore, be taken in the storage, moving and handling of such discs to avoid causing any such imperfections. As used herein, the term compact disc or CD is intended to encompass all such discs, whatever their size, for all known or proposed uses.
Compact discs containing laser recorded information are typically packaged in enclosures designed to hold one or more CDs for protecting the discs during storage and shipment. Enclosures commonly used at the present time comprise a three piece assembly consisting of a base or bottom element, an insert or tray in the base/bottom element for positioning and supporting the disc in the base/bottom element, e.g., by a center projection (commonly referred to as a "rosette") which engages the periphery of the aperture in the center of the disc, and a lid or cover which is hinged to the base/bottom element and is closed thereon after the disc is mounted therein on the tray. Other enclosures utilize only two pieces, omit the tray, and position and support the disc via the center projection directly on the base/bottom element. The enclosure is, typically, at least partially transparent and graphics relating to the disc and containing trademark and sales promotional information are usually inserted in such a manner as to be visible through the enclosure.
It has become conventional for the elements of the CD enclosures to be formed by injection molding. As a consequence the rosettes are formed of the same plastic material as the base or tray with which they are integrally molded. The base and/or tray elements and, therefore, the rosettes have typically been made from pigmented thermoplastic molding resins having sufficient impact resistance to withstand the forces attendant to mounting and unmounting CDs as well as the forces experienced during shipping and handling.
Most typically, the rosette comprises a raised hub which is formed integrally with the base/bottom element or tray, preferably by injection molding. The hub includes a plurality of small gripping teeth or fingers for radially engaging the central aperture in the CD. Generally, to mount a CD onto the rosette, the central aperture of the CD is positioned over the rosette and a slight downward pressure is applied. Due to the relative dimensions of the central aperture and the rosette, the downward pressure causes the gripping teeth or fingers to deflect radially inwardly and to resiliently engage the central aperture of the CD. In this way the rosette engages and secures the CD in place during storage. To remove a CD from the rosette, the top center of the rosette is pressed down with one finger to disengage the teeth or fingers while the periphery of the CD is simultaneously lifted. One of the problems with many currently available enclosures is that, because it is difficult to continuously push on the top center of the rosette while lifting, frequently, release pressure on the top of the rosette is not maintained while lifting pressure on the periphery is increased. The result is that the disc is forced off of the rosette, causing the CD to bent or broken and the rosette to be damaged.
There have been many attempts to make disc removal easier and less damaging. For example, U.S. Pat. No. 4,793,479--Otsuka et al discloses dis-engagement structure in which the rosette is provided with a central pushing part having cranked flap pieces arranged such that pressing down on the pushing part causes the cranked flap pieces to push the disc off the disc-engagement structure. U.S. Pat. No. 5,251,750--Gelardi et al teaches a rosette having upwardly extending engagement arms for engaging the center hole of a disc at their upper ends and which extend radially inwardly for connection with a center button, the engagement arms having integrally molded upwardly extending ejection arms at their lower end for engaging the underside of the disc. When the center button is depressed the upwardly extending ejection arms push upwardly on the underside of the disc to release its engagement with the upper end of the engagement arms. U.S. Pat. No. 5,788,068--Fraser et al discloses a central disk retaining member comprising two resilient inwardly extending radial arms cantilevered from the base portion and interconnected at their inner ends to provide a central button-like member, the arms being formed with disk-retaining overhanging lips to retain the disk on the member. To release a disk from engagement with the member, the central button is depressed, causing the arms to rotate downwardly and inwardly, to allow the disk to be lifted over the overhanging lips.
However, efforts to date directed at solving the disc removal problem suffer from one or more shortcomings which make the resulting rosette either unsatisfactory or not particularly desirable for use in a CD enclosure. This is because prior art rosettes are, typically, either of complex construction and, therefore, uneconomical to manufacture or unacceptably fragile and unreliable in use, which presents substantial risk of damaging the information bearing surface of the disc. Accordingly, there remains a need for a simple, inexpensive to manufacture and easy to use rosette for a CD enclosure which is configured to facilitate safe mounting and unmounting of the disc thereon and which does not present a damage risk for the disc's information bearing surface.